Weapon-mounted targeting display devices cooperate with a firearm scope to present certain targeting information within a sight picture (or field of view (FOV)) that presents an image of a target. Such targeting display devices thus enable a shooter to view the target and the targeting information simultaneously without breaking cheek-to-stock weld, or otherwise losing target awareness. Such display devices may communicate with a ballistic computer (also referred to as a “calculator” or “solver”) that calculates a ballistic solution using known equations and variables including bullet type, range to target, cant angle, angle of incline/decline to target, wind speed and direction, elevation, temperature, humidity, and barometric pressure, for example, measured by various sensors. The ballistic solution generated by the ballistic computer may then be displayed in various forms by a display unit to the shooter.
Various known targeting display devices generate a digitally reproduced image of a target, and overlay targeting information on the digitally reproduced image. A notable disadvantage of this design is that upon an unintended power failure of the display device, the digitally reproduced image generated by the display device disappears, leaving the shooter unable to view the target directly with the scope. Others have attempted to integrate an entire system into a single optical device or to display limited information. Accordingly, there is a need for improvement to address these and other shortcomings of known firearm-mounted targeting display devices.